Various solutions are known in the state of the art, which provide the user of a cellular telephone a means for triggering an alarm message in a so-called panic situation. The NOKIA company has provided a first solution provided on its website “How to use your telephone as a panic button” at the following address: http://www.developer.nokia.com/Community/Wiki/How_to_use_your_telephone_as_a_panic_button. This solution consists in enabling, in case of a given alert, to dial a telephone number and to send a SMS (short message) to the contacts saved.
The American patent application U.S. 2008/0030350 also provides for a cellular telephone equipped with a specific panic button for activating a broadcast and/or sound message. Another American patent application U.S. 2002/0183037 provides another solution as a dedicated button for activating an alarm message to deter aggressors.
The European Patent EP1629449 describes a portable communication device intended to be held by an individual and used in conjunction with a Bluetooth-enabled cellular telephone. It is used to communicate a signal indicating the existence of an emergency to a base station and comprises a pendant-shaped housing, wherein a first interface circuit is arranged, which comprises a pair of activation switches triggered by alarm buttons in order to facilitate the input of a signal in the device indicating the existence of an emergency. A microprocessor reads the signals in the first interface circuit and reads the last determined position of the device using a GPS positioning circuit in the housing. It also reads the identity of the device, the telephone number of the base station whereto the message relative to the existence of an emergency situation from a programmable memory must be communicated. The microprocessor prepares an activation signal which comprises the identity and the position of the device, the telephone number of the base station and the message which is sent with a time tag to the portable telephone via a Bluetooth sender/receiver. The activation signal activates the portable telephone so as to transfer the data contained in the activation signal to the base station.
The solutions of the prior art are not entirely satisfactory. The solutions based on the addition of a dedicated alarm button are limited to telephones initially designed to implement this feature, and do not make it possible to upgrade a fleet of existing telephones, nor enable a user to upgrade his/her telephone to incorporate this feature. As for the solutions of the prior art providing for the triggering of an alarm from an application installed on the telephone, the drawback is that the activation of an alert requires more actions by the user. To send the alarm, the following is required:                1) Unlock the screen if it is locked or if the user is using another application, click on the Home button to return to the home screen of the telephone;        2) Find the application icon on the telephone home screen and click thereon to open the application;        3) On the home screen of the application, click on “call” or an alert icon and confirm sending the SMS.        
This sequence of actions is not adapted to implementation in panic situations, e.g. an assault, an accident or an illness. Besides, some emergency call applications can be operated under certain circumstances only, for instance, when the telephone is locked, or unlocked, or in standby mode.